Electric induction relay with two auxiliary phase windings counteracting each other



Mi. s 1'932. w, H PETERS 1,848,270

ELECTRIC INDUCTION RELAY WITH TWO AUXILIARY PHASE WINDINGS COUNTERACTING EACH OTHER Filed June 12, 1951 W We fg/01w? Patented Mar. 8, 1932 WILHELM HENNING PETERSEN, OF VASTERAS, SWEDEN, ASSIGNOR TO ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET, E VASTERAS, SWEDEN, A CORPORATION 01' SWEDEN ELECTRIC INDUCTION RELAY WITH TWO AUXILIARY PHASE WINDINGS COUNTER- ACTING EACH OTHER Application iiled .Tune 12, 1931, Serial No. 543,908, and in. Sweden June 12, 1980.

The present invention relates to an electric constant time limit relay of induction type which is intended to act as an intermediary agent between a primary relay and a controlling device, for instance between a voltage relay and a ratio adjuster for a transformer, said relay having the characteristic feature that the primary relay will have to break and close only a very small power and therefore can be made very sensitive. The invention utilizes the arrangement known per se of two auxiliary windings (shading coils) on a common electro-magnet,

counteracting each other, and is characterized by the fact that the stronger one of the said auxiliary phase windings is normally open but provided with means for being short-circuited by the primary relay, while the weaker auxiliary phase winding is permanently short-circuited.

A form of the invention is diagrammatically illustrated in the accompanying draw-' ings, in two views perpendicular to each other in Figs. 1 and 1 is a coil of the electro-magnet, 2 its iron core and 3 the induction disc. The iron core 2 has adjacent to the air gap embracing the induction disc two auxiliary phase windings 4, 5, which are placed on either side of the tree portion 6 of the said iron core and therefore act to rotate the disc 3 in opposite directions. One of the auxiliary phase windings 4 is permanently short-circuited, while the other 5 is normally open and connected to a pair of contacts 7, over which it can be short-circuited by means of a primary relay 8. The auxiliary phase winding 4 is the weaker one, that is. it contains either less copper or embraces less iron than the winding 5, preferably both as has been indicated in the drawings. The primary relay 8 is for instance connected to the voltage of a power system, and the coil 1 may be connected to the same voltage.

The disc 3 is influenced by a braking magnet 9 in a known maner and is mounted on a shaft 10 which also carries an arm 11 which normally bears against a stop 12 under the influence of the torque produced by the auxiliary phase winding 4. When the auxiliary phase winding 5 is closed by the relay 8, the disc is started in the clock-wise direction and after a certain time presses a contact piece 13 on the arnr 11 against a pair of fixed contacts 14 and thereby closes a circuit, for instance through a controlling motor for a transformer ratio ad'uster.

By deriving the setting force and the counteracting force of the relay from the same voltage coil 1, an inferior variation of the voltage will have no essential influence on the time of function of the relay. In the same time, the movements of the relay obtain the softness and freedom from shocks which are characteristic to induction relays in general. The volt-ampere number in the auxiliary phase winding 5 can be kept very low (in most cases occurring in practice less than 1 V. A.), which enables the primary relay 8 to be very sensitive.

I claim as my invention: 7

Electric induction relay comprising an electro-magnet, an auxiliary hase winding thereon adapted to be short-circuited by an auxiliary relay, a permanently short-circuited auxiliary phase winding thereon weaker than and counter-acting the first-named winding, an induction disc cooperating with said electromagnet and contacts operated by said disc.

In testimony whereof I have signed my name to this specification.

WILHELM HENNING PETERSEN. 

